Unlocking the Potential of Nanoparticles Composed of Immiscible Elements for Direct H₂O₂ Synthesis

Today, multimetallic nanoparticles (NPs) are extensively studied to search for high-performance catalysts. Unfortunately, a huge material space of NPs composed of immiscible elements has been generally disregarded for catalyst development due to the inherent difficulty of alloy synthesis. Herein, for the direct synthesis of hydrogen peroxide (H₂O₂), we demonstrate that NPs of immiscible elemental combinations of Rh–Ag, Rh–Au, Pt–Au, and Ir–Ag can efficiently produce H₂O₂, despite the negligible activities of Rh, Pt, Ir, Ag, and Au alone. In particular, we show that two catalysts, Rh₁₃Ag₈₇ and Pt₂₈Au₇₂ NPs, can outperform prototypic Pd NPs. Rh₁₃Ag₈₇ NPs, owing to their high content of the less-expensive element Ag, exhibit a 7.3-fold enhancement in cost-normalized productivity compared to Pd and, thus, may serve as an economical option. The other catalyst of Pt₂₈Au₇₂ NPs exhibits a productivity of 300 mmol g_cat^–1 h^–1 and a 15-fold increase over that of Pd under isoconversion conditions. The observed remarkable productivities of these NPs are a result of the synergy between the two elemental domains at the interface. The present study suggests that the hitherto underutilized space of immiscible elemental combinations should be more actively searched for the development of improved catalyst materials.